FOAM-MEDIATED DISPLACEMENT OF OIL Russian patent published in 2002 - IPC

FIELD: oil and gas production. SUBSTANCE: aqueous solution of polymer is injected into well as preceding plug. In particular, noncondensing gas and aqueous solution of foam-forming composition are periodically injected, simultaneously or successively, to form underground bound foam, or bound foam, preliminarily formed from aforesaid noncondensing gas and aqueous solution under overground conditions, is periodically injected into well, said aqueous solution of foam-forming composition containing alkali, surfactant, and polymer. Once foam plug is formed, displacement of oil by injected water is continued. EFFECT: increased oil recovery due to increased coefficient of coverage and completeness of displacement. 16 cl, 5 tbl